Transcatheter prosthetic heart valve delivery system with protective feature

ABSTRACT

Delivery devices for a stented prosthetic heart valve. The delivery device includes a spindle, at least one cord, and a covering feature associated with the spindle for selectively covering at least a portion of a stented prosthetic heart valve tethered to the spindle in a delivery state. In some embodiments, the covering feature includes a tip mounted to the spindle. The tip can include an overhang region for selectively covering a portion of the stented prosthetic heart valve. In other embodiments, the tip can include a tip body and a compressible foam bumper. In yet other embodiments, the covering feature includes an outer sheath arranged to selectively cover the stented prosthetic heart valve. The outer sheath can be elastic and stretchable for recapturing a partially expanded prosthesis, for example by including one or more windows covered by a stretchable covering layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Non-Provisional Patent Application claims the benefit of the filingdate of U.S. Provisional Patent Application Ser. No. 62/345,957, filedJun. 6, 2016, entitled “Transcatheter Prosthetic Heart Valve DeliverySystem with Protective Feature,” the entire teachings of which areincorporated herein by reference.

BACKGROUND

The present disclosure relates to transcatheter stented prosthetic heartvalve delivery and deployment. More particularly, it relates totranscatheter delivery systems, devices and methods that guard againstvascular damage.

A human heart includes four heart valves that determine the pathway ofblood flow through the heart: the mitral valve, the tricuspid valve, theaortic valve, and the pulmonary valve. The mitral and tricuspid valvesare atrio-ventricular valves, which are between the atria and theventricles, while the aortic and pulmonary valves are semilunar valves,which are in the arteries leaving the heart. Ideally, native leaflets ofa heart valve move apart from each other when the valve is in an openposition, and meet or “coapt” when the valve is in a closed position.Problems that may develop with valves include stenosis in which a valvedoes not open properly, and/or insufficiency or regurgitation in which avalve does not close properly. Stenosis and insufficiency may occurconcomitantly in the same valve. The effects of valvular dysfunctionvary, with regurgitation or backflow typically having relatively severephysiological consequences to the patient.

Diseased or otherwise deficient heart valves can be repaired or replacedusing a variety of different types of heart valve surgeries. Oneconventional technique involves an open-heart surgical approach that isconducted under general anesthesia, during which the heart is stoppedand blood flow is controlled by a heart-lung bypass machine.

More recently, minimally invasive approaches have been developed tofacilitate catheter-based implantation of the valve prosthesis on thebeating heart, intending to obviate the need for the use of classicalsternotomy and cardiopulmonary bypass. In general terms, an expandablevalve prosthesis is compressed about or within a catheter, insertedinside a body lumen of the patient, such as the femoral artery, anddelivered to a desired location in the heart.

The heart valve prosthesis employed with catheter-based, ortranscatheter, procedures generally includes an expandable multi-levelframe or stent that supports a valve structure having a plurality ofleaflets. The frame can be contracted during percutaneous transluminaldelivery, and expanded upon deployment at or within the native valve.With one type of stented prosthetic heart valve designs, the stent frameis formed to be self-expanding. The valved stent is crimped down to adesired size and held in that compressed state within a sheath or byother means for transluminal delivery. Retracting the sheath (or otherrelease operation) from this valved stent allows the stent toself-expand to a larger diameter, fixating at the native valve site. Inmore general terms, then, once the prosthetic valve is positioned at thetreatment site, for instance within an incompetent native valve, thestent frame structure may be expanded to hold the prosthetic valvefirmly in place. One example of a stented prosthetic valve is disclosedin U.S. Pat. No. 5,957,949 to Leonhardt et al., which is incorporated byreference herein in its entirety.

SUMMARY

With some recently considered transcatheter delivery devices andmethods, the prosthetic heart valve is compressed and held over aspindle of the device by one or more sutures (or similar material). Todeploy the prosthesis, tension in the sutures is slowly released. Whileviable, these and similar techniques may give rise to undesirableatraumatic contact between portions of the compressed prosthetic heartvalve and the patient's vasculature during delivery. In addition, it maybe difficult to recapture the prosthetic heart valve relative to thedelivery device once tension in the sutures has been released.

The inventors of the present disclosure recognize that a need exists fortranscatheter prosthetic heart valve delivery systems and methods thatovercome one or more of the above-mentioned problems.

Some aspects of the present disclosure are directed toward deliverydevices for a stented prosthetic heart valve. The delivery deviceincludes a spindle, at least one cord, and a covering feature associatedwith the spindle for selectively covering at least a portion of astented prosthetic heart valve tethered to the spindle in a deliverystate. In some embodiments, the covering feature includes a tip mountedto the spindle. The tip can include an overhang region for selectivelycovering a portion of the stented prosthetic heart valve. In otherembodiments, the tip can include a tip body and a compressible foambumper. In yet other embodiments, the covering feature includes an outersheath arranged to selectively cover the stented prosthetic heart valve.The outer sheath can be elastic and stretchable for recapturing apartially expanded prosthesis, for example by including one or morewindows covered by a stretchable covering layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view of a stented prosthetic heart valve useful withthe delivery devices of the present disclosure and in a normal, expandedcondition;

FIG. 1B is a side view of the stented prosthetic heart valve of FIG. 1Ain a compressed condition;

FIG. 2 is a perspective, exploded view of components of a deliverydevice in accordance with principles of the present disclosure;

FIG. 3 is a simplified cross-sectional view of a portion of the deliverydevice of FIG. 2 upon final assembly;

FIG. 4A is a simplified side view of a stented prosthetic heart valveand the delivery device of FIG. 2 in a tethered and expanded state;

FIG. 4B is a simplified cross-sectional view of the arrangement of FIG.4A;

FIG. 5A is a simplified cross-sectional view of the components of FIG.4A in a delivery state, including the stented prosthetic heart valvecinched to a compressed condition;

FIG. 5B is a simplified side view of the arrangement of FIG. 5A;

FIG. 6 is a simplified side view of the components of FIG. 4A andillustrating complete deployment of the stented prosthetic heart valvefrom the delivery device;

FIG. 7 is a cross-sectional view of a tip in accordance with principlesof the present disclosure and useful with the delivery devices of thepresent disclosure;

FIG. 8A is a cross-sectional view of the tip of FIG. 7 in a deflectedarrangement;

FIG. 8B is a cross-sectional view of the tip of FIG. 7 in an invertedarrangement;

FIG. 9A is a simplified cross-sectional view of a portion of system inaccordance with principles of the present disclosure in an initialloading state, the system including a stented prosthetic heart valve anda delivery device, and the delivery device including the tip of FIG. 7;

FIG. 9B illustrates the system of FIG. 9A in a delivery state;

FIG. 9C illustrates the system of FIG. 9B in a deployment state;

FIG. 10A is a perspective view of another tip in accordance withprinciples of the present disclosure;

FIG. 10B is an enlarged view of a portion of the tip of FIG. 10A;

FIG. 11 is a simplified cross-sectional view of another tip inaccordance with principles of the present disclosure;

FIG. 12 is a simplified cross-sectional view of a portion of system inaccordance with principles of the present disclosure in a deliverystate, the system including a stented prosthetic heart valve and adelivery device, and the delivery device including the tip of FIG. 11;

FIG. 13A is a simplified perspective view of a portion of an outersheath in accordance with principles of the present disclosure anduseful with the delivery devices of the present disclosure;

FIG. 13B is a simplified, longitudinal cross-sectional view of a portionof the sheath of FIG. 13A;

FIG. 14A is a cross-sectional view of the sheath of FIG. 13B, takenalong the line 14A-14A;

FIG. 14B is a cross-sectional view of the sheath of FIG. 13B, takenalong the line 14B-14B;

FIG. 15A is a simplified top view of a portion of the sheath of FIG.13A;

FIG. 15B is a simplified top view of a portion of another sheath inaccordance with principles of the present disclosure;

FIG. 16 is the cross-sectional view of FIG. 14A illustrating the sheathin an expanded condition;

FIG. 17A is a simplified side view of a portion of system in accordancewith principles of the present disclosure in a delivery state, thesystem including a stented prosthetic heart valve and a delivery device,and the delivery device including the outer sheath of FIG. 13A;

FIG. 17B is a simplified side view of the system of FIG. 17A andillustrating the outer sheath in a retracted position; and

FIG. 17C is a simplified side view of the system of FIG. 17A andillustrating the outer sheath recapturing the stented prosthetic heartvalve.

DETAILED DESCRIPTION

Specific embodiments of the present disclosure are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. The terms “distal” and“proximal” are used in the following description with respect to aposition or direction relative to the treating clinician. “Distal” or“distally” are a position distant from or in a direction away from theclinician. “Proximal” and “proximally” are a position near or in adirection toward the clinician. Although the present disclosure isdescribed with reference to preferred embodiments, workers skilled inthe art will recognize that changes can be made in form and detailwithout departing from the spirit and scope of the present disclosure.

As described below, some aspects of the present disclosure relate totranscatheter valve delivery devices utilizing one or more flexiblecords (e.g., sutures, wires, filaments, etc.) to compress and retain astented prosthetic heart valve during delivery to a target site. By wayof background, stented prosthetic heart valves useful with the deliverydevices of the present disclosure can be a bioprosthetic heart valvehaving tissue leaflets or a synthetic heart valve having polymeric,metallic or tissue-engineered leaflets, and can be specificallyconfigured for replacing any of the four valves of the human heart, orto replace a failed bioprosthesis, such as in the area of an aorticvalve or mitral valve, for example.

In general terms, the stented prosthetic heart valves useful with thedevices and methods of the present disclosure include a stent or stentframe maintaining a valve structure (tissue or synthetic), with thestent frame having a normal, expanded condition or arrangement andcollapsible to a compressed condition or arrangement when loaded to adelivery device. The stent frame is normally constructed to self-deployor self-expand when released from the delivery device. The stents orstent frames are support structures that comprise a number of struts orwire segments arranged relative to each other to provide a desiredcompressibility and strength to the prosthetic heart valve. The strutsor wire segments are arranged such that they are capable oftransitioning from a compressed or collapsed condition to a normal,radially expanded condition. The struts or wire segments can be formedfrom a shape memory material, such as a nickel titanium alloy (e.g.,Nitinol™). The stent frame can be laser-cut from a single piece ofmaterial, or can be assembled from a number of discrete components.

With the above understanding in mind, one simplified, non-limitingexample of a stented prosthetic heart valve 20 useful with systems,devices and methods of the present disclosure is illustrated in FIG. 1A.As a point of reference, the stented prosthetic heart valve 20 is shownin a normal or expanded condition in the view of FIG. 1A; FIG. 1Billustrates the stented prosthetic heart valve 20 in a compressedcondition (e.g., when compressed or cinched to a delivery device asdescribed below). The stented prosthetic heart valve 20 includes a stentor stent frame 22 and a valve structure 24. The stent frame 22 canassume any of the forms mentioned above, and is generally constructed tobe self-expandable from the compressed condition (FIG. 1B) to thenormal, expanded condition (FIG. 1A). Further, the stent frame 22defines or terminates at opposing, first and second ends 30, 32.Structural features such as crowns 34, eyelets 36, posts, etc., areformed or carried by the stent frame at one or both of the ends 30, 32.

The valve structure 24 can assume a variety of forms, and can be formed,for example, from one or more biocompatible synthetic materials,synthetic polymers, autograft tissue, homograft tissue, xenografttissue, or one or more other suitable materials. In some embodiments,the valve structure 24 can be formed, for example, from bovine, porcine,equine, ovine and/or other suitable animal tissues. In some embodiments,the valve structure 24 can be formed, for example, from heart valvetissue, pericardium, and/or other suitable tissue. In some embodiments,the valve structure 24 can include or form one or more leaflets 40. Forexample, the valve structure 24 can be in the form of a tri-leafletbovine pericardium valve, a bi-leaflet valve, or another suitable valve.In some constructions, the valve structure 24 can comprise two or threeleaflets that are fastened together at enlarged lateral end regions toform commissural joints, with the unattached edges forming coaptationedges of the valve structure 24. The leaflets 40 can be fastened to askirt that in turn is attached to the frame 22. The side-by-sidearrangement of the leaflets 40 establishes commissures 42, one of whichis identified in FIG. 1B.

With the one exemplary construction of FIGS. 1A and 1B, the stentedprosthetic heart valve 20 can be configured (e.g., sized and shaped) forreplacing or repairing an aortic valve. Alternatively, other shapes arealso envisioned, adapted to mimic the specific anatomy of the valve tobe repaired (e.g., stented prosthetic heart valves useful with thepresent disclosure can alternatively be shaped and/or sized forreplacing a native mitral, pulmonic or tricuspid valve). Thus, in thevarious delivery device embodiments described below, where reference ismade to the stented prosthetic heart valve (or prosthesis) 20, a shapeof the prosthesis 20 is generically illustrated, reflecting that theprosthesis 20 can assume any shape in the normal, expanded condition.

By way of further background, FIG. 2 illustrates one non-limitingexample of general components of a delivery device 50 with which someembodiments of the present disclosure are useful. The delivery device 50includes an inner shaft 60, a plurality of cords (such as cords 62 a-62c), an optional tension control rod 64, an optional release pin 66, anda handle assembly 68. The inner shaft 60 extends from the handleassembly 68 and includes or carries a spindle 70 connected to a tip 72.One or more lumens (not shown) are defined in the inner shaft 60 (andextend to the spindle 70). The tension control rod 64 is connected tothe handle assembly 68 and is slidably disposed within one of the lumensof the inner shaft 60. As described in greater detail below, the cords62 a-62 c (e.g., sutures, wires, filaments, etc.) are each coupled at afixed end thereof to the tension control rod 64, and extend through theinner shaft 60. Where provided, the release pin 66 is also connected tothe handle assembly 68, and is slidably disposed within another lumen ofthe inner shaft 60 for selectively engaging and releasing a free end ofthe each of the cords 62 a-62 c. The handle assembly 68 includes one ormore actuators 74 for user-prompted longitudinal movement of the tensioncontrol rod 64 and of the release pin 66 relative to each other andrelative to the inner shaft 60. The handle assembly 68 can incorporateaddition control mechanisms actuating other optional components of thedelivery device 50. For example, an outer sheath assembly 80 isoptionally provided, forming a capsule 82 that can be slidably disposedover the inner shaft 60.

Assembly of the delivery device 50 is generally reflected by thesimplified cross-sectional representation of FIG. 3. As a point ofreference, for ease of illustration, individual lumens formed within theinner shaft spindle 70 are not shown in FIG. 3 or in any othersimplified cross-sectional representation of the present disclosure. Thetension control rod 64 is connected to a fixed end of the each of thecords 62 a-62 c. The cords 62 a-62 c are flexible and substantiallyinextensible bodies (e.g., sutures, wires, filaments, etc.). The cords62 a-62 c extend from the tension control rod 64, and individually passthrough a respective hole or port (not shown) in the spindle 70. Asidentified in FIG. 3, each of the cords 62 a-62 c terminates at a freeend 90. With embodiments in which three of the cords 62 a-62 c areprovided, relative to the arrangement of FIG. 3, the first cord 62 aserves as a proximal cord, the second cord 62 b serves as anintermediate cord, and the third cord 62 c serves as a distal cord. Inother embodiments, more or less than three of the cords 62 a-62 c can beincluded with the delivery device 50. The optional release pin 66 isslidably disposed within a separate lumen of the spindle 70 for reasonsmade clear below.

FIGS. 4A and 4B illustrate, in simplified form, the stented prostheticheart valve 20 as initially loaded to the delivery device 50. A lengthof each of the cords 62 a-62 c extending from the tension control rod 64wraps about or engages a circumference of the prosthesis 20. The freeend 90 of each of the cords 62 a-62 c is directed into the spindle 70and brought into engagement with the release pin 66 (e.g., the free end90 can from a loop that slidably receives the release pin 66).Alternatively, the release pin 66 can be omitted, with the free end 90being routed through the inner shaft 60 and back to the handle assembly68 (FIG. 2). Once connected, the stented prosthetic heart valve 20 andthe delivery device 50 collectively define a system 100.

The stented prosthetic heart valve 20 can then be compressed or cinchedonto the spindle 70 by proximally retracting the tension control rod 64as reflected in the simplified view of FIGS. 5A and 5B. The release pin66, and thus the free end 90 of each of the cords 62 a-62 c engagedtherewith, remains stationary during proximal movement of the tensioncontrol rod 64. Thus, proximal retraction of the tension control rod 64tensions the cords 62 a-62 c and shortens the length of each cord 62a-62 c outside of the spindle 70, in turn forcing the prosthesis 20 toradially collapse or compress. FIGS. 5A and 5B represented a deliverystate of the system 100 (in which the prosthesis 20 has been compressedor cinched onto the delivery device 50). In the delivery state, thesystem 100 is manipulated to deliver the prosthetic heart valve 20 viathe patient's vasculature (or other percutaneous approach). Once thedelivery device 50 has been directed to locate the prosthetic heartvalve 20 at the targeted native valve site, the tension control rod 64can be distally advanced relative to the spindle 70 back toward thearrangement of FIGS. 4A and 4B. Proximal advancement of the tensioncontrol rod 64 releases tension in the cords 62 a-62 c, allowing theprosthesis 20 to self-expand to or toward the normal, expanded conditionreflected by the views. Relative to the order of steps, when returned tothe arrangement of FIGS. 4A and 4B, the system 100 (i.e, the deliverydevice 50 and the prosthetic heart valve 20 in combination) is referredto throughout this disclosure as being in a tethered and expanded state(i.e., the prosthetic heart valve 20 has self-reverted to the normal,expanded condition, and remains connected or tethered to the deliverydevice 50 by the cords 62 a-62 c). The free end 90 of each of the cords62 a-62 c is then released from engagement with the release pin 66 asreflected by FIG. 6 (e.g., where the free ends 90 each are or include aloop slidably received over the release pin 66, the release pin 66 canbe proximally retracted until removed from engagement with the free ends90). The tension control rod 64 can then be proximally retracted,withdrawing the cords 62 a-62 c from the prosthetic heart valve 20 andinto the inner shaft spindle 70. With the prosthesis 20 now fullyreleased, the delivery device 50 can be withdrawn from the patient.

With the above in mind, some embodiments of the present disclosure aredirected toward delivery device constructions that address possibleconcerns raised as the system 100, in the delivery state, is trackedthrough a patient's vasculature. For example, one embodiment of a tip120 useful with the delivery devices of the present disclosure (e.g., analternate for the tip 70 of FIG. 2) is shown in FIG. 7. The tip 120 canbe an integral, homogenous body extending between opposing, distal andproximal ends 122, 124. An exterior shape of the tip 120 defines a tipregion 130, a transition region 132, and an overhang region 134. Acentral passage 136 extends from, and is open at, the proximal end 124and is optionally open to the distal end 122.

A shape of the tip region 130 is selected to facilitate atraumaticinterface with tissue of a patient akin to conventional catheter tipdesigns. For example, the tip region 130 can include a trailing section140 and a leading section 142 extending from the trailing section to 140to the distal end 122. The trailing section 140 can have a relativelyuniform outer diameter. The leading section 142 tapers in outer diameterfrom the trailing section 140 in a direction of the distal end 122.Thus, an outer diameter of the tip 120 at the distal end 122 is lessthan an outer diameter of the trialing section 140.

The transition region 132 extends between the tip and overhang regions130, 134, and is generally configured to robustly maintain a shaft (notshown) as described below. In some embodiments, a radial shoulder 144 isdefined at an intersection of the transition region 132 and the trailingsection 140 of the tip region 130, generated by an outer diameter of thetransition region 132 being less than the outer diameter of the trailingsection 140.

The overhang region 134 extends from the transition region 132 to theproximal end 124. A shape of the overhang region 134 defines aninversion section 150 and a cover section 152. The inversion section 150has an increasing or expanding outer diameter shape or geometry inproximal extension from the transition region 132 to the cover section152. The cover section 152 can have a relatively uniform outer diameterin extension to the proximal end 124. A wall thickness of the overhangregion 134, at least along the cover section 152 and a majority of theinversion section 150, is reduced (as compared to a wall thickness ofthe transition region 132). The wall thickness, material, and otheroptional attributes of, or features incorporated into, the overhangregion 134 allow the cover section 152 to readily expand in diameter inresponse to an applied force, and the overhang region 134 to assume aninverted arrangement relative to the transition region 132 as describedbelow.

The central passage 136 can have a relatively uniform diameter along thetip region 130, sized, for example, to slidably receive a guidewire (notshown). A diameter of the central passage 136 along the transitionregion 132 is greater than the diameter along the tip region 130. Thechange in diameter defines a lip 160. The change in diameter (and thusthe lip 160) can be formed within the tip region 130 as shown.Regardless, the central passage 136 along the transition region 132 issized, for example, to receive a shaft (not shown), including the shaftabutting the lip 160 as described below. A diameter and shape of thecentral passage 136 along the overhang region 134 mimics thedescriptions above, expanding in the proximal direction from thetransition region 132, and being relatively uniform along the coversection 152. The central passage 136 can be viewed as forming a cavity162 within the overhang region 134.

FIG. 7 represents a normal arrangement of the tip 120. Flexibility ordeformability of the overhang region 134 can include the overhang region134 readily increasing in outer diameter in response to an appliedforce, for example being forced to the deflected arrangement reflectedin FIG. 8A by a radially outward force applied to an interior of theoverhang region 134 by an external source (not shown). The cover section152 can be elastically forced to a differing angle relative to theinversion section 150 (as compared to the angle of the normalarrangement of FIG. 7), for example. In the deflected arrangement, adiameter of the cavity 162 increases from the transition region 132 tothe proximal end 124. Upon removal of the force, the overhang region 134self-transitions back to the normal arrangement or shape of FIG. 7. Insome embodiments, a material and construction (e.g., wall thickness) ofthe tip 120 is such that the overhang region 134 is readily forced to,and self-reverts from, a wide variety of deflected shapes. Otherfeatures are optionally included that further enhance deformation orflexing of the overhang region 134 to the deflected arrangement, such asa slit, line of weakness, etc.

The overhang region 134 can further be reversibly forced from the normalarrangement of FIG. 7 to an inverted arrangement or shape as shown inFIG. 8B. In the inverted arrangement, the overhang region 134 primarilyextends in the distal direction over the transition region 132, locatingthe proximal end 124 proximate the tip region 130. In some embodiments,the tip 120 is configured (e.g., material, geometry, etc.) so that auser can manually “flip” the overhang region 134 from the normalarrangement to the inverted arrangement (and vice-versa). A wallthickness of the transition region 132 can be greater than a wallthickness of the inversion section 150 of the overhang region 134,providing a base against which or relative to which the overhang region134 can be deflected to and from the inverted arrangement.

A variety of manufacturing techniques can be employed to provide the tip120 with the elastic deformation characteristics described above. Forexample, the tip 120 can be formed by an over-molding process in which amaterial of the tip 120 is molded over a mandrel having a shapecorresponding to the central passage 136 as described above (or carryingan insert with the desired shape).

The above-described, elastically deformable nature of the tip 120, andin particular of the overhang region 134, promotes loading of thestented prosthetic heart valve 20 (FIG. 1) to the delivery device 50(FIG. 2), and subsequent deployment of the prosthesis 20 from thedelivery device 50. For example, FIG. 9A illustrates, in simplifiedform, a portion of a system 100A including a delivery device 50A and thestented prosthetic heart valve 20 in an initial stage of loading. Thedelivery device 50A includes the spindle 70 and the tip 120. The spindle70 is disposed within the central passage 136, optionally abutting thelip 160. The tip 120 can be secured to the spindle 70 via a bond(adhesive, welding, etc.) along the transition region 132. The stentedprosthetic heart valve 20 has been disposed over and collapsed orcinched onto the spindle 70 by the cords 62 a-62 c (two of which arevisible in FIG. 9A) as described above with respect to FIGS. 5A and 5B.Prior to collapsing the prosthesis 20 on to the spindle 70, the tip 120is forced or manipulated to the inverted arrangement as shown. A distalsegment 170 of the stented prosthetic heart valve 20 is located slightlyproximal the transition region 132. As a point of reference, the distalsegment 170 can be either of the prosthesis ends 30, 32 (FIG. 1A),depending upon an orientation of the stented prosthetic heart valve 20relative to the delivery device 50A. Regardless, the distal segment 170can include structural features (not shown) of the stent frame 22 (FIG.1A) such as the crowns 34, eyelets 36, posts, etc. (FIG. 1A) asdescribed above.

Subsequently, the overhang region 134 is returned (e.g., manuallymanipulated by a user) to the normal arrangement as in FIG. 9B tocomplete loading of the stented prosthetic heart valve 20. In thedelivery state of FIG. 9B, the overhang region 134 overlies the distalsegment 170, covering any of the structural features (not shown) carriedor formed thereby. In other words, crowns, eyelets, posts, etc., of thedistal segment 170 are covered by the overhang region 134.

The system 100A (in the delivery state) is then manipulated to locatethe stented prosthetic heart valve 20 at or adjacent a target site(e.g., a native heart valve to be repaired). As the system 100A istracked through the patient's vasculature, the distal segment 170remains covered by the overhang region 134, even as the system 100Atraverses tight or complex “turns” in the native anatomy. The structuralfeatures of the distal segment 170 are never exposed, and thus do notcause damage to the patient's vasculature during delivery. Further,because the distal segment 170 is covered, increased friction forcesthat might otherwise occur were the distal segment 170 exposed arebeneficially avoided.

Once the stented prosthetic heart valve 20 is desirably located, tensionin the cords 62 a-62 c is then slowly released as described above,allowing the prosthesis 20 to self-revert toward the normal, expandedcondition. As stented prosthetic heart valve 20 radially expands, thedistal segment 170 exerts a radially outward force on to the overhangregion 134. As shown in FIG. 9C, the overhang region 134 readily assumesthe deflected arrangement in response to this applied force, allowingthe prosthesis 20 to completely release from the tip 120, and thus thedelivery device 50A. With the overmold (or similar) design of someembodiments of the present disclosure, an actuator or other mechanism isnot required to permit release of the prosthesis 20 from the tip 120.

While the tip 120 has been described as being an integral, homogeneousbody, other constructions can be employed. For example, the tip region130 and the transition region 132 can be formed as a first body, and theoverhang region 134 from as a second body that is assembled to the firstbody. With this approach, a material (and resulting thickness) of theseparately-formed overhang region 134 can differ from that of the tipand transition regions 130, 132 (e.g., the tip and transition regions130, 132 can be a relatively thick walled molded plastic whereas theoverhang region is a thin wall, flexible tube (akin to a sock)).Alternatively or in addition, the overhang region 134 can be formed tohave a varying wall thickness. In this regard, another embodiment of atip 120A in accordance with principles of the present disclosure isshown in FIG. 10A. The tip 120A is akin to the tip 120 (FIG. 7), andinclude or forms the tip region 130 and the transition region 132 aspreviously described. An overhang region 134A is also provided, and canbe similar to the overhang region 134 (FIG. 7) described above. However,the overhang region 134A can have a varying thickness and incorporateother geometry features as illustrated in FIG. 10B.

Another embodiment tip 200 in accordance with principles of the presentdisclosure and useful with delivery devices of the present disclosure(e.g., as the tip 72 of the delivery device 50 of FIG. 2) is shown insimplified form in FIG. 11. The tip 200 includes a tip body 202 and abumper 204. The tip body 202 can be akin to tips conventionally employedwith transcatheter delivery devices (e.g., a molded plastic material),and extends between a distal end 210 and a proximal end 212. The tipbody 202 is shaped or formed to define a tip region 220, a transitionregion 222, and a central passage 224. The tip region 220 can be similarto the tip region 130 (FIG. 7) described above, having a tapering outerdiameter in a direction of the distal end 210. The transition region 222can have a relatively uniform outer diameter in extension from the tipregion 220 to the proximal end 212. The central passage 224 extendsfrom, and is open to, the proximal end 212. Commensurate with the abovedescriptions, the central passage 224 can further be open to the distalend 210, having a diameter along the tip region 220 sized to slidablyreceive a guide wire (not shown) or similar implement. Along thetransition region 222, the central passage 224 can be sized and shapedto receive the spindle 70 (FIG. 2) as described below.

The bumper 204 is disposed or formed over an exterior surface of thetransition region 222, and has a deformable or compressibleconstruction. For example, in some embodiments the bumper 204 is a foammaterial, such as an open cell or closed cell foam. Non-limitingexamples of foam materials useful with or as the bumper 204 include atwo part polyurethane foam that can be “painted” on the transitionregion 222, injection molded on to the transition region 222, pourmolded on to the transition region 222, etc. Regardless, the bumper 204is configured to readily radially compress or deform when subjected toan external force.

The above-described, compressible nature of the bumper 204 promotesloading of the stented prosthetic heart valve 20 (FIG. 1) to thedelivery device 50 (FIG. 2), and subsequent deployment of the prosthesis20 from the delivery device 50. For example, FIG. 12 illustrates, insimplified form, a portion of a system 100B including a delivery device50B and the stented prosthetic heart valve 20 in an initial stage ofloading. The delivery device 50B includes the spindle 70 and the tip200. The spindle 70 is disposed within the central passage 224. The tip200 can be secured to the spindle 70 via a bond (adhesive, welding,etc.) along the transition region 222. The stented prosthetic heartvalve 20 has been disposed over and collapsed or cinched onto thespindle 70 by the cords 62 a-62 c (two of which are visible in FIG. 12)as described above with respect to FIGS. 5A and 5B. A portion of thedistal segment 170 of the stented prosthetic heart valve 20 is locatedto interface with the bumper 204. More particularly, the distal segment170 includes or terminates in one or more structural features, such ascrowns, posts, eyelets, etc. These terminal structural features arerepresented schematically in FIG. 12 at 230. With collapsing of thestented prosthetic heart valve 20 on to the spindle 70, the structuralfeatures 230 embed into the bumper 204, with a material of the bumper204 compressing or deforming about the structural features 230.Optionally, a cord (not shown) can be routed about the structuralfeatures and tightened to further draw the structural features 230 intothe bumper 204. Regardless, in the delivery state of FIG. 12, the bumper204 essentially covers at least a leading edge of the structuralfeatures 230.

The system 100B (in the delivery state) is then manipulated to locatethe stented prosthetic heart valve 20 at or adjacent a target site(e.g., a native heart valve to be repaired). As the system 100B istracked through the patient's vasculature, the structural features 230remain at least partially covered by the bumper 204, even as the system100B traverses tight or complex “turns” in the native anatomy. At leastthe leading edge of the structural features 230 is effectively neverexposed, and thus do not cause damage to the patient's vasculatureduring delivery.

Once the stented prosthetic heart valve 20 is desirably located, tensionin the cords 62 a-62 c is then slowly released as described above,allowing the prosthesis 20 to self-revert toward the normal, expandedcondition. As stented prosthetic heart valve 20 radially expands, thestructural features 230 readily release from the bumper 204, allowingthe prosthesis 20 to completely release from the tip 200, and thus thedelivery device 50B.

Returning to FIG. 2 and as mentioned above, in some embodiments, thedelivery devices of the present disclosure optionally include the outersheath 80 carrying or forming the capsule 82. Where provided, the outersheath 80 and the capsule 82 can be configured to selectively cover aloaded and collapsed stented prosthetic heart valve 20 (FIG. 1B) duringdelivery, as well facilitate recapture of a partially expandedprosthesis. For example, a portion of an outer sheath 300 useful withsome delivery devices of the present disclosure (e.g., as the outersheath 80 and/or the capsule 82) is illustrated in simplified form inFIGS. 13A and 13B. The outer sheath 300 terminates at a distal end 302,and defines a lumen 304. In some embodiments, the outer sheath 300 has amulti-layer construction as described below. Further, the outer sheath300 can be diametrically expandable or stretchable in certain regions,such as by forming one or more windows. The windows can include one ormore distal windows, such as distal windows 310 a, 310 b, and one ormore intermediate windows, such as intermediate windows 312 a, 312 b(the first intermediate window 312 a being visible in the view of FIG.13A, and the second intermediate window 312 b being visible in the viewof FIG. 13B).

With specific reference to FIG. 13B, the multi-layer construction of theouter sheath 300 includes an inner layer 320 and an outer layer 322. Theinner and outer layers 320, 322 are both tubular members, with the outerlayer 322 being formed over the inner layer 320 (e.g., co-extrusionprocess). For reasons made clear below, a covering layer 324 is furtherprovided, and can be formed at select regions (e.g., location(s) of thewindow(s)) or can extend an entire length of the outer sheath 300.

Materials of the inner and outer layers 320, 322 are selected in tandemto provide desired longitudinal rigidity and hoop strength (e.g.,appropriate for recapturing a partially expanded stented prostheticheart valve (not shown)), as well as a low friction surface along thelumen 304 (e.g., appropriate for free sliding movement of a guide wire(not shown) within the lumen 304). For example, the inner layer 320serves as a liner and can be a thin, low friction plastic material, suchas polytetrafluoroethylene (PTFE), or other conventional cathetermaterial or blend of materials. A material or material blend of theouter layer 322 is selected to provide desired hoop strength andlongitudinal robustness. In some non-limiting embodiments, the outerlayer 322 is or includes a Nylon 12 material, such as Grilamid TR 55™available from EMS-GRIVORY of Sumter, S.C.

In tubular form, the outer layer 322 is inherently resistant todiametric expansion or stretching. However, where provided, the distalwindow(s) 310 a, 310 b impart an expandable or stretchable attributeinto the outer sheath 300 at a corresponding distal region 330 of theouter sheath 300 for reasons made clear below. As best shown in FIG.13B, each of the distal windows 310 a, 310 b represent an absence ofmaterial of, or cut-out through a thickness of, at least the outer layer322, and optionally of the inner layer 320. With additional reference toFIG. 14A, while two of the distal windows 310 a, 310 b are illustrated,in other embodiments, a greater or lesser number can be provided. Wheretwo or more are provided, the distal windows 310 a, 310 b can beuniformly sized and spaced relative to a circumference of the outersheath 300. In related embodiments, the two distal windows 310 a, 310 bare diametrically opposed. The distal window(s) 310 a, 310 b can extendto the distal end 302, and can have the square or rectangular-like shapegenerally reflected by FIG. 15A. Other shapes are also acceptable, suchas triangular (e.g., as in FIG. 15B), complex, etc.

Returning to FIGS. 13A and 13B, where provided, the intermediatewindow(s) 312 a, 312 b impart an expandable or stretchable attributeinto the outer sheath 300 at a corresponding intermediate region 332 ofthe outer sheath 300 for reasons made clear below. As shown in FIG. 14B,the optional intermediate windows 312 a, 312 b represent an absence ofmaterial of, or cut-out through a thickness of, at least the outer layer322 and optionally the inner layer 320. While two of the intermediatewindows 312 a, 312 b are illustrated, in other embodiments a greater orlesser number can be provided. Where two or more are provided, theintermediate windows 312 a, 312 b can be uniformly sized and spacedrelative to a circumference of the outer sheath 300. In relatedembodiments, the two intermediate windows 312 a, 312 b are diametricallyopposed. A longitudinal length of the intermediate window(s) 312 a, 312b is selected to generate desired diametric expandability into the outersheath 300. For example, where a partially expanded stented prostheticheart valve (not shown) is to be recaptured and located within theintermediate region 332, a length of the intermediate window(s) 312 a,312 b can be increased. With an increased length of the intermediatewindow(s) 312 a, 312 b, a minimum diameter of the lumen 304 required forrecapturing the prosthesis can be decreased (thus decreasing an overallprofile of the outer sheath 300).

Returning to FIGS. 13A and 13B, the outer sheath 300 can include onlythe distal window(s) 310 a, 310 b, only the intermediate window(s) 312a, 312 b, or both the distal and intermediate window(s) 310 a-312 b.With the non-limiting example of FIGS. 13A and 13B, the distal windows310 a, 310 b are rotationally offset from the intermediate windows 312a, 312 b by approximately ninety degrees.

The covering layer 324 is a thin material body extending across each ofthe windows 310 a-312 b. In some embodiments, the covering layer 324 istubular in nature, and can be applied only in regions of the windows 310a-312 b; in other embodiments, the covering layer 324 is continuous.Regardless, the covering layer 324 is an elastically stretchable polymermaterial or material blend (e.g., a thermoplastic polyether-urethaneblend, akin to a film. One non-limiting example of a material blenduseful as the covering layer 324 is 70% polyether-urethane (e.g.,available under the trade designation Elasthane™ from DSM BiomedicalInc. of Berkeley, Calif.), 20% siloxane, and 10% tie resin (e.g., aresin available under the trade designation Plexar® from LyondellBasellIndustries of Houston, Tex.). Other materials and material blends arecontemplated.

The covering layer 324 provides structural integrity to the outer sheath300 in regions of the window(s) 310 a-312 b, and maintains thisstructural integrity while facilitating diametric stretching orexpansion. For example, FIG. 14A reflects a normal or un-stretchedcondition of the outer sheath 300. In response to a radially outwardforce applied to an interior of the outer sheath 300, the inner andouter layers 320, 322 diametrically (and circumferentially) expand atthe distal windows 310 a, 310 b as reflected by FIG. 16 (i.e., ascompared to the condition of FIG. 14A, an arc length of the windows 310a, 310 b has increased). Further, the covering layer 324 diametrically(and circumferentially) stretches, and continues to cover the distalwindows 310 a, 310 b thereby maintaining an overall structural integrityof the outer sheath 300 in the expanded condition of FIG. 16. Thus, theouter sheath 300 has an initial diameter D1 (at least at a region of thedistal windows 310 a, 310 b) in the normal condition, and an increased,expanded diameter D2 in the expanded condition.

The above-described, expandable nature of the outer sheath 300 promotesloading of the stented prosthetic heart valve 20 (FIG. 1) to thedelivery device 50 (FIG. 2), and subsequent recapture of prosthesis 20when partially expanded. For example, FIG. 17A illustrates, insimplified form, a portion of a system 100C including a delivery device50C and the stented prosthetic heart valve 20 in an initial stage ofloading. The delivery device 50C includes cords 62 a-62 c, the spindle70 and the outer sheath 300 (drawn transparent in FIGS. 17A and 17B forease of understanding). The stented prosthetic heart valve 20 has beendisposed over and collapsed or cinched onto the spindle 70 by the cords62 a-62 c as described above. The outer sheath 300 is advanced distallyover the collapsed stented prosthetic heart valve 20 such that thedistal end 302 of the outer sheath 300 is distal the distal segment 170of the prosthesis 20. Thus, any structural features (e.g., crowns,posts, eyelets, etc.) included with or carried by the distal segment 170are covered or within the outer sheath 300.

The system 100C (in the delivery state) is then manipulated to locatethe stented prosthetic heart valve 20 at or adjacent a target site(e.g., a native heart valve to be repaired). As the system 100C istracked through the patient's vasculature, the distal segment 170 (andthe structural features provided therewith) remains covered by the outersheath 300, even as the system 100C traverses tight or complex “turns”in the native anatomy. The structural features are never exposed, andthus do not cause damage to the patient's vasculature during delivery.Further, with optional embodiments in which the covering layer 324 (FIG.13B) is provided at the distal region 330 (FIG. 13A) of the outer sheath300 and includes siloxane or similar material, the siloxane or similarmaterial adds lubricity to the outermost surface of the outer sheath 300for improved tracking.

Once the stented prosthetic heart valve 20 is desirably located, theouter sheath 300 is retracted from over the prosthesis 20. Tension inthe cords 62 a-62 c is then slowly released as described above, allowingthe prosthesis 20 to self-revert toward the normal, expanded condition.Prior to completely releasing the cords 62 a-62 c from the stentedprosthetic heart valve 20, the clinician may desire to re-position theprosthesis 20 relative to the native anatomy or remove the prosthesis 20from the patient. Under these and other circumstances, tension isre-applied to the cords 62 a-62 c, causing the stented prosthetic heartvalve 20 to collapse back on to the spindle 70. It may be difficult tofully collapse the prosthesis 20 in situ using only the cords 62 a-62 c.FIG. 17B reflects this possibility, with the prosthesis 20 slightlyexpanded relative to the spindle 70. The outer sheath 300 can then bedistally advanced back over the partially expanded stented prostheticheart valve 20 to assist in recapture, as shown in FIG. 17C. In thisregard, the outer sheath 300 readily diametrically stretches or expandsin the regions of the windows 310 a-312 b (two of which are generallyidentified in the view) to accommodate the slightly enlarged outerdiameter of the partially expanded stented prosthetic heart valve 20 (ascompared to the outer diameter of the prosthesis in the delivery state(FIG. 17A)).

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A delivery device for delivering a stentedprosthetic heart valve including a valve structure carried by a stentframe configured to self-expand from a collapsed condition to a normal,expanded condition, the delivery device comprising: an inner shaftforming a lumen; a spindle associated with the inner shaft; and acovering feature associated with the spindle for selectively covering atleast a portion of a stented prosthetic heart valve positioned over thespindle in a delivery state; the covering feature having a proximal endand a distal end; wherein the covering feature includes a tip mounted tothe spindle; wherein the tip defines a tip region, a transition regionand an overhang region, the overhang region defining an inversionsection adjacent the transition region and a cover section at theproximal end, the transition region having an outer diameter that isless than an outer diameter of the cover section, wherein the tip regiondefines a radial shoulder at the transition region; and further whereinthe overhang region is configured to transition from a normalarrangement in which the cover section is not positioned over thetransition region to an inverted arrangement in which the inversionsection is folded so that the cover section is positioned over thetransition region, wherein the inversion section terminates proximal tothe radial shoulder in the inverted arrangement.
 2. The delivery deviceof claim 1, wherein the overhang region is configured to cover a distalportion of the stented prosthetic heart valve in the delivery state. 3.The delivery device of claim 2, wherein the overhang region extendsproximally from the transition region in the normal arrangement of thetip.
 4. The delivery device of claim 3, wherein the overhang regiondefines a first inner diameter in the normal arrangement; wherein thetip is configured to be transitionable from the normal arrangement to adeflected arrangement in which the overhang region defines a secondinner diameter, the second inner diameter being greater than the firstinner diameter.
 5. The delivery device of claim 1, wherein the overhangregion has a variable wall thickness.
 6. The delivery device of claim 1,wherein the tip is an integral, homogeneous body.
 7. The delivery deviceof claim 1, wherein the transition region is positioned between the tipregion and the overhang region; wherein a central passage extendsthrough the tip region, transition region and the overhang region. 8.The delivery device of claim 7, wherein the central passage defines alip in the tip region; wherein the spindle abuts the lip.
 9. Thedelivery device of claim 1, wherein the inversion section has anincreasing outer diameter from the transition region to the coversection.
 10. The delivery device of claim 1, wherein the coveringfeature is an integral, homogenous body.
 11. The delivery device ofclaim 1, wherein a central passage continuously extends from theproximal end to the distal end and a shape of the central passage isdefined by the tip region, the transition region and the overhangregion.
 12. A delivery device for delivering a stented prosthetic heartvalve including a valve structure carried by a stent frame configured toself-expand from a collapsed condition to a normal, expanded condition,the delivery device comprising: an inner shaft forming a lumen; aspindle associated with the inner shaft, wherein the spindle defines afirst hole open to the lumen and an exterior of the spindle; a firstcord slidably disposed within the lumen for selectively compressing astented prosthetic heart valve; and a covering feature associated withthe spindle for selectively covering at least a portion of a stentedprosthetic heart valve tethered to the spindle in a delivery state; thecovering feature having a proximal end and a distal end; wherein thecovering feature includes a tip mounted to the spindle; wherein the tipdefines a tip region having a radial shoulder, a transition region andan overhang region, the overhang region defining an inversion sectionadjacent the transition region and a cover section at the proximal end,the transition region having an outer diameter that is less than anouter diameter of the cover section; wherein the inversion section hasan inverted arrangement in which the inversion section is positionedover the transition section and terminates proximal to the radialshoulder.
 13. The delivery device of claim 12, wherein a central passagecontinuously extends from the proximal end to the distal end and a shapeof the central passage is defined by the tip region, the transitionregion and the overhang region.
 14. The delivery device of claim 13,wherein the central passage defines a lip in the tip region; wherein thespindle abuts the lip.